The role of Controlled and Mole Drainage in Relation to Water Saving, Salt Accumulation on Sugar Beet Yield and Quality in North Nile Delta, Egypt

Two field experiments were conducted at Sidi Salem region, Kafr El-Sheikh Governorate, Egypt, during two winter seasons 2018/2019 and 2019/2020 to study the impact of controlled drainage at 0.5, 0.75, 1.25 m and mole drain spacing 2 m on soil salinity, water-saving and sugar beet productivity. Results obtained that using controlled drainage saved irrigation water 24.56 and 11.35% in 1st season and 23.73 and 15.08% in 2nd season for 50, 75 cm depth of water table respectively, compared to 125 cm depth of water table. Application of mole drains seems to be more effective in decreasing soil salinity and sodicity especially, in the topsoil (0-60 cm) and narrow spacing between the plowed lines (2 m).Data showed that the water table level at 0.5 and 0.75 m treatments rose more rapidly and remained higher for longer time than the uncontrolled drainage treatment, the average water table depth was above specified depths between irrigation intervals from 3-7 days depending on the depth. There was a marked variation between the treatments that controlled drainage increased the yield at 0.50 m water table depth by 39 and 30% for both seasons, respectively. It can be concluded that the treatment of controlled drainage may give more profit than the uncontrolled one. At the same time, the contents of K+, Na+, alpha- amino N and alkalinity in root beet were insignificantly affected by controlled subsurface drainage in both seasons.